One of prior arts of interest to the present invention is disclosed in Japanese Utility Model Laying-Open Gazette No. 153240/1979 (which corresponds to U.S. Pat. No. 4,275,876, issued June 30, 1981). This prior art is an electrophotographic copying machine structured such that a part of a copy paper transporting path from a paper supplying portion to a paper ejecting portion is made into one unit and the unit is structured in a manner capable of being drawn in the copy paper transporting direction from the copying machine main body. More specifically, this prior art is structured such that most of the copy paper transporting path including a transferring portion, a fixing portion and a paper ejecting roller, a copy paper storing portion and a paper supplying roller, is made into one unit. And, the same is adapted such that, when a paper jam (a jam) occurs at a part of the copy paper transporting path, the unit is drawn in the copy paper transporting direction, whereby the copy paper having caused the paper jam is easily taken out. However, in this prior art, the paper supplying roller remains attached to the copying machine main body side, since it is impossible to draw all of the copy paper transporting path including a paper supplying cassette for the reason to be described subsequently. Accordingly, on the occasion of a paper jam having occurred in the close vicinity of a paper supplying end, it is necessary to insert a hand into the vicinity of the photosensitive drum to draw out the copy paper in the direction perpendicular to the transporting direction. Such is not different from the conventional devices having been known prior to this prior art, and such involves a possibility of injuring the photosensitive drum or a sufficient possibility of touching the photosensitive drum by the hand. Accordingly, in this prior art, there remains the drawback of the conventional arts, that is, the possibility of injuring the photosensitive drum or of touching the photosensitive drum on the occasion of taking out the copy paper having caused the paper jam, and it is impossible to say that an entire improvement has been made compared to the conventional arts.
Another example of the prior art described in Japanese Patent Laying-Open Gazette No. 12335/1978, laid open on Feb. 3, 1978. In this prior art, differing from the above described prior art, a part of the copy paper transporting path from the paper supplying portion to the photosensitive drum is made into an integrated unit, and the unit is structured to be capable of moving in the direction parallel with the radial direction of the photosensitive drum, or the copy paper transporting direction. This other prior art also relates to an improvement in making it easy the copy paper on the occasion a paper jam. However, in this prior art, since it is impossible to draw portions other than the paper supplying portion, it is necessary to insert a hand into the interior of the main body as before on the occasion of the paper jam at portions of a developing apparatus or a drying roller, whereby there is a great probability of touching the photosensitive drum. Meanwhile, in this prior art, it is impossible to make the transporting path and the paper supplying portion as a unit and to draw the unit. The reason is that the copying machine described in Japanese Patent Laying-Open Gazette No. 12335/1978 is adapted to make liquid development, whereby the developer is split on the occasion of the developing apparatus portion being structured to move, and, therefore, this prior art does not teach or suggest anything about the movement of transporting path portions other than the paper supplying portion at all.
It is believed that the above described two prior art devices are most closely related to the present invention. However, as described above, both of the two prior art devices still have the shortcomings of the conventional art devices which were already known prior to the two prior art devices. More specifically, both of the two prior art devices are not structured such that all of the copy paper transporting path can be withdrawn to the exterior of the machine body, and, therefore, there is a high probability that a hand of a person will come into contact with the photosensitive drum and damage it. The photosensitive drum used in the electrophotographic copying machine, in general, must not be touched by a human hand. The reason is that the performance of sensing light extremely deteriorates when fat on a human hand adheres to the surface of the photosensitive drum. Accordingly, in the electrophotographic copying machine using such a photosensitive drum, there must not be a possibility of the human hand coming into contact with the photosensitive drum, at all.
Accordingly, a primary object of the present invention is to provide an electrophotographic copying machine in which there is no danger that a human hand may come into contact with the photosensitive drum or damage the photosensitive drum removing a copy paper jammed in the machine.
The electrophotographic copying machine in accordance with the present invention is structured such that the copy paper transporting path from the paper supplying end to the paper ejecting end is divided into two assembly units, each of the assembly units being capable of being drawn from a predetermined attached position at the exterior of the machine body in a direction opposite from each other and a parallel with the transporting direction of the copy papers. According to the present invention, since the copy paper transporting path is divided into two assembly units and one or both of the assembly units can be withdrawn due to the structure permitting the removal of each of the assembly units to the exterior of the machine body, there is no necessity to insert a hand into the main body and thus there is no danger that a human hand will come into contact with the photosensitive drum on the occasion of a paper jam in any portions of the copy paper transporting path. In order to eliminate the possibility that a human hand will come into contact with the photosensitive drum, all of the transporting path is structured to be withdrawn at one side of the machine body in the direction parallel to the copy paper transporting path. However, in the case where all of the transporting path is structured to be drawn as one unit, it is necessary to structure the machine body or the transporting path unit to be very strong and thus the size of a machine must be large. Therefore, the entire copying machine becomes extremely heavy, since a large moment occurs on the occasion of withdrawing the assembly and a particularly very large moment occurs on the occassion of withdrawing all of the unit. In addition, on the occasion of withdrawing the transporting path, the position of the center of gravity of the copying machine shifts outside the machine main body, so that there is the danger that the entire machine will fall down. In contrast with the above described, in accordance with the present invention, if the transporting path is divided into two assembly units and either one or both of the same are withdrawn as occasion demands, it is not necessary to make the assembly units or the machine body as strong, and thus not as large or heavy. In addition, in the copying machine having two-divided copy paper transporting path in accordance with the present invention, removing the copy paper is done easily because only one assembly unit of the side where a paper jam occurs is removed. More specifically, a copy paper in the paper supplying portion or the paper ejecting portion sometimes causes a paper jam with the same being able to be seen from the exterior, or the paper jam does not always occur at the intermediate portion of the transporting path. In such a case, since it is possible to know easily which assembly unit the paper jam occurs in, it is necessary only to withdraw only the assembly unit in question, and thus it is possible to remove the copy paper more easily as compared with a machine adapted to withdraw all of the transporting path. In addition, since the assembly units can be removed in opposite directions from each other, the center of gravity of the copying machine does not move very much and thus stability is enhanced.
A preferred embodiment of the present invention is structured such that a fixing apparatus includes a heating apparatus for heating a toner, and one of the two assembly units includes the above described heating apparatus and the paper ejecting portion and the other of them includes a part of the copy paper transporting path from the paper supplying portion of the heating apparatus. According to this preferred embodiment, on the occasion of a paper jam in a portion other than the heat fixing portion, since it is necessary only to draw one of the two assembly units, in which the paper jam has occurred, it is not necessary for an operator to take excessive avoid the heat by the heating means in order to prevent a burn, and thus rapid handling can be done. In addition, since the heating apparatus and the copy paper transporting path from the paper supplying portion to the heating apparatus are separated from each other, it is difficult for the heat generated by the heating apparatus to be transmitted to other portions, and thus it is rare that the other portions are influenced by the heat. Accordingly, it is preferred that the assembly unit not including a heat generating portion comprises as many portions of the copy paper transporting path as possible in accordance with the present invention.
According to another preferred embodiment of the present invention, there is provided an opening at a chassis side plate thereof, through which the copy paper transporting path can be inspected from the exterior of the machine body. This opening may be formed along at least the copy paper transporting path. According to the embodiment, as the copy paper transporting path can be inspected from the exterior, it is easy to recognize the position where a paper jam has occurred. It is thus necessary to withdraw only the assembly unit where the paper jam has occurred in order to remove the copy paper, and it is not necessary to move another assembly unit. It is also possible to remove the copy paper having caused the paper jam extremely easily and rapidly.
The preferred embodiment of the present invention is structured such that the two assembly units are provided movably on at least two parallel rails formed on the bottom plate of the machine body. The rails have the additional function of enhancing the strength of the bottom plate, and accordingly, even if the plate thickness of the bottom plate is not made so thick, there is no danger that distortion of the machine body occurs on the occasion of withdrawing the assembly units.
A pair of parallel rails are provided for each of the two assembly units. One pair of parallel rails has its length from the paper supplying end longer than at least a half of the total length of the bottom plate in the copy paper transporting direction but shorter than the total length thereof and the other pair of the parallel rails extends from the paper ejecting end and have its length longer than at least a half of the total length of the bottom plate but shorter than the total length thereof. In such a way, the rails need not be provided over all of the total length of the bottom plate in the copy paper transporting direction, and thus it is necessary only to be longer than at least a half of the total length. If so, since the four rails are arranged at the central portion in the direction of the length of the bottom plate, where the strongest rigidity is needed, in parallel in a manner to be distributed in the direction of the width of the same, it is possible to obtain the rigidity required at the portion easily.
A further preferred embodiment of the present invention is structured to pivotally support a guide cover, provided from the paper supplying end to the transferring portion, at the backward position in the drawing direction, thereby to construct the guide cover in a manner capable of being opened at the front position in the drawing direction. According to the embodiment, it is possible to remove the copy paper having caused a paper jam easily by opening the guide cover. In addition, since the guide cover is pivotally supported at the backward position in the drawing direction of the assembly units, it is not necessary to open the guide cover completely in order to remove the copy paper having caused the paper jam, and thus it is possible to minimize the length of the assembly units withdrawn.
Meanwhile, in an electrophotographic copying machine provided with a manual paper supplying portion in addition to a paper supplying cassette, the automatic paper supplying portion including the paper supplying cassette and the manual paper supplying portion are integrated to be made into one assembly unit.
A still further embodiment of the present invention is structured to include as a fixing apparatus a combination of a heating roller and a pressing roller, to divide one of assembly units into a portion including the heating roller and a portion including the pressing roller and to pivotally attach these two divided portions to each other, thereby to make it possible that to easily remove the copy paper having caused the paper jam by opening the interior of one of the assembly units. Meanwhile, if one of the assembly units is divided into two portions in such a way, which are adapted to be able to be opened, the enhancement of the efficiency of the work on the occasion of the inspection of the interior can be expected.
Meanwhile, circuit parts including a power source, or a power source unit, are integrated with one of the assembly units including the paper supplying portion, and an electric power necessary for the other of the assembly units including the heating apparatus is supplied through a connector. The connector has three-divided connector terminals, one of the connector terminals being attached to one of the assembly units, the other of the connector terminals being attached to the other of the assembly units, and the intermediate connector terminal for connecting between these two connector terminals being fixed to the machine body bottom plate at the center therebetween. The power may be distributed at a distribution point of the main body to be supplied to the two assembly units through connectors.
In addition, the power supply from one of the assembly units to the other of the assembly units or the power supply from the main body to the two assembly units may be achieved by means of a connecting cable capable of extending and contracting or a connecting cable being flexible.
According to a still further preferred embodiment of the present invention, the fixing of the assembly units to the respective attached positions is achieved by a lock mechanism. More specifically, in the assembly units, there are provided an actuating lever whose one end projects to the exterior of the machine body, a coupling lever coupled to the actuating lever in a manner capable of swinging, and a lock lever coupled to the coupling lever in a manner capable of swinging and having an engaging portion for selectively engaging an engaged portion formed in the machine body of the copying machine. The actuation of the actuating lever causes the release of the engagement relationship between the engaging portion of the lock lever and the engaged portion of the machine body of the copying machine. According to this embodiment, since it is possible to withdraw the assembly units only by actuating the actuating lever, the handling of a paper jam can be done more rapidly.